While single-node configurations are acceptable for small environments, testing or POCs most production environments will require a multi-node configuration for various reasons. As we know multi-node configurations group similar OpenStack services and provide scalability as well as the possibility for high availability. One of the great things about OpenStack is the architecture. Every service is decoupled and all communication between services is done through RESTful API endpoints. This is the model architecture for a cloud. The advantages are that we have tremendous flexibility in how to build a multi-node configuration. While a few standards have emerged there are many more possible variations and in the end, we are not stuck to a rigid deployment model. The standards for deploying multi-node OpenStack are as a two-node, three-node or four-node configuration. Add compute node on existing openstack using packstack installation.

You have installed OpenStack all-in-one with PackStack on your setup. In this tutorial, we will extend existing OpenStack installation (Controller node, Compute node) with new Compute-node1 on-line, without shutting down existing nodes. The easiest and fastest way to extend existing OpenStack Cloud on-line is to use Packstack. We will see how to add Compute Node on Existing OpenStack using Packstack.Existing nodes:
Installed as all-in-one with packstack